With continuous development of electronic technologies, a terminal, such as a smartphone, a tablet computer, and an electronic book (eBook) reader, that includes a touchscreen is increasingly popular.
When a user performs a touch operation on the touchscreen to control the terminal, a finger of the user is prone to obstruct content displayed on the touchscreen. To minimize an obstruction of the screen caused by the touch operation by the user, for an existing terminal, independent touch keys are usually disposed outside the touchscreen of the terminal, and these touch keys are correspondingly set as commonly-used function keys such as a menu key, a return key, and a home key. With a structure similar to the touchscreen, the touch keys may include a complete capacitance node, and the capacitance node may include two layers of conductors that are insulated from each other. When the user touches the touch key, a charge transfer occurs between an upper-layer conductor of the capacitance node and the finger, accordingly, a capacitance of the capacitance node changes, and the terminal may detect, according to the change of the capacitance, that the user performs a touch control operation on the touch key, and then perform a function instruction corresponding to the touch key.
The existing touch keys disposed outside the touchscreen are independent touch detection components that need to occupy a given space of a terminal. Therefore, a relatively small quantity of touch keys are usually disposed, and corresponding functions are limited, which causes poor user experience.